The B&W caterpillars (Lophpcampa caryae) are NOT poisonous. The have urticating hair-like setae which can be irritating to the skin (similar to stinging nettles if anyone has come across that). This is one of a number of native caterpillars with similar long setae which can irritate the skin but they should not be killed, just use caution and don't pick them up if you are concerned.

JoAnne Russo
Saxtons River, VT 

    On Monday, September 16, 2019, 4:24:15 AM EDT, Jane Stein <[log in to unmask]> wrote:  
 I'm personally strongly disinclined to kill any living thing.  My concern
was whether these moths/caterpillars were harmful to trees, etc.  a la
gypsy moths.  I've lived through a couple of major and destructive gypsy
moth events, so I'm a wee bit paranoid.  But I just looked these guys up
and learned that they don't do a lot of damage to trees.


On Sun, 15 Sep 2019 20:17:07 +0000, Ryan Tomazin <[log in to unmask]>
> Sorry, but there are lots of caterpillars that have these defense
> mechanisms. There is no need to kill them. I don't mean anything
> here, but these are native moths.
> Ryan Tomazin - Pittsburgh, PA
> ________________________________
> From: Vermont Birds <[log in to unmask]> on behalf of Jane Stein
> <[log in to unmask]>
> Sent: Sunday, September 15, 2019 4:07 PM
> To: [log in to unmask] <[log in to unmask]>
> Subject: Re: [VTBIRD] Take care
> Thanks very much for the warning!  I saw one of these yesterday and
> wondered what it was, but left it alone.  Are these bad guys and should
> they be squashed?
> Jane
> (Shoreham)
> On Sun, 15 Sep 2019 15:25:27 -0400, DAVID MOSHER <[log in to unmask]>
> wrote:
>> Right now there seems to be a lot of white & black fuzzy caterpillars
> out
>> there. Do not pick them up. They are the White HIckory Tussock Moth
>> caterpillar. They are poisonous, can sting and the resulting rash can
> send
>> you to the Doctor’s. Kids are curious and like to pick up fuzzy
>> caterpillars. Take care out there.
>> Dave